1. Field of Invention
The invention relates generally to detecting and processing vibrational cardiac data, and more specifically to apparatuses and methods used to detect vibrational cardiac data related to coronary artery disease.
2. Art Background
Coronary artery disease is a primary precursor of heart attacks, which is a leading cause of death in the United States. Coronary artery disease is characterized by a deposition of plaque within the coronary arteries, resulting in a condition referred to as stenosis, in which case blood flow is restricted and the oxygen supply to the heart muscle is decreased. Such a deposition of plaque is also referred to as an occlusion. Coronary artery disease can result in heart attack and subsequent physical injury and possible death. This can present a problem.
It is known that the blood flow can become turbulent as the blood passes through an area of stenosis. Turbulent blood flow provides a source of vibrational excitation within the body. The vibrational excitation causes energy to propagate through the body and provides a field that can be measured at the surface of the body. Normal body functions such as breathing and the opening and closing of the heart's valves provide high levels of background noise relative the magnitude of the vibrational energy resulting from excitation at areas of stenosis. Such high levels of background noise can frustrate detection. This can present a problem.
The body is made up of structures that have very different physical properties which are distributed as a function of space throughout the body cavity. Some of these structures are lungs, ribs, organs, blood, arteries, fat, etc. These structures present a non-homogeneous media to the propagation of vibrational energy. Such a non-homogenous media can make it difficult to characterize the media sufficiently to form focused listening beams while processing the vibrational energy emitted from the areas of stenosis during a parametric analysis that assumes a known vibrational wave speed. This can present a problem.
Currently, coronary artery disease is treated post symptomatically with an invasive procedure called an angiogram. The angiogram is costly, invasive, and places the patient at risk of injury due to complications that can arise during the procedure. All of this can present problems.